Kyle Chalmers has needed four cortisone injections for a debilitating back injury before securing his spot at a third Olympic Games.
Chalmers pushed through the pain to win the 100m freestyle at Australia's Olympic selection trials on Thursday in Brisbane.
On a night when Kaylee McKeown again fell just shy of another world record, Chalmers revealed that just 10 days ago he had doubts of swimming at all when his lower back locked.
"I have got bulging discs in my back and a bit of a degenerative spine ... it just all spasmed and locked up," he said.
"It was a really hard thing to go through so close to trials.
"I have put on a pretty brave face.
"The good thing is that mentally and emotionally, I'm in a very, very good spot so I'm able to rise above the adversity and the challenges that have been thrown at me.
"And that's only because it has happened so many times throughout my career that I've had to rise above something."
Chalmers, the 100m freestyle Olympic champion in 2016 and silver medallist at the Tokyo Games of 2021, won in 47.45 seconds with William Yang (48.08) second.
Earlier, McKeown insisted she wasn't bothered by coming close to breaking her own 200m backstroke world record.
With 10 metres remaining, she was under record pace but touched in two minutes 03.30 seconds, outside her benchmark 2:03.14 set in March last year.
"It doesn't bother me at all," said McKeown, who admitted to pre-race nerves.
"To be honest with you, I'm just happy to still be swimming around that time, not many people in the world are doing that at the moment.
"You're putting your heart on the line, you've done months worth of hard training ... and you just want to do yourself proud.
"And with that comes nerves unfortunately."
McKeown's near-miss follows another on Tuesday night when she snuck within eight-hundredths of a second of her 100m backstroke world record.
The 22-year-old's triumph came as 32-year-old Emily Seebohm finished fifth and, after having a baby eight months ago, failed to become the first Australian swimmer selected for five Olympics.
Meanwhile, Ariarne Titmus - just 24 hours after breaking the women's 200m world record - cruised to victory in the women's 800m freestyle.
Titmus finished in 8:14.06 from Lani Pallister (8:18.46).
In the women's 200m butterfly, Liz Dekkers (2:06.01) prevailed with Abbey Connor (2:06.82) second.
And in the men's 200m individual medley, William Petric triumphed in 1:57.54 with McKeown's partner Brendon Smith second in 1:58.12.
Both were outside the automatic qualifying Olympic time set by Swimming Australia with their Paris hopes resting with selector's discretion.
